The present invention concerns chain lubricants for conveyer and transport systems, especially in the foodstuff industry, which are suitable for lubrication, cleaning and disinfection of the transport chains. Furthermore, the invention concerns the process for the use of this chain lubricant.
The invention preferably concerns the lubrication of conveyoer and transport chains in filling plant for foodstuffs, preferably of drinks which are filled into glass or synthetic material bottles, tins or other drink containers.
In the filling operation, the above containers are transported during the filling to various stations, for example cleaning stations, filling stations, labelling stations, packing stations. This usually takes place by means of conveying and transport plant which usually, for reasons of hygiene and corrosion protection, consist of stainless steel but the transport chain can also be of synthetic material. Such plant are, in the following, designated as conveying plant.
In order to reduce mechanical stressing of containers and transport plant, a sufficient lubrication of the transport bands is necessary in order that the band can be further moved unhindered even when the containers on the band can sometimes not be moved forwards.
If the conveying plant are not lubricated to a sufficient extent, this can, on the one hand, have the result that the containers fall over or, on the other hand, that they do not stop although the corresponding filling, cleaning or labelling station is reached. Both kinds of disturbances can lead to comparatively long stationary times of the conveying plant and thus to considerable decreases of capacity. On the other hand, the lubrication is not to be so strong that the containers, already in the case of small counterforces, are no longer taken along by the transport band, i.e. especially in the case of transfer from one conveyor band to the other, in the case of ascending or descending bands or in the case of insertion into the working stations are not sufficiently conveyed.
Besides the lubricating action, in the case of conveying plant in the foodstuff industry, there is necessary especially also a cleaning and disinfecting, especially biostatic action of the chain lubricant.
The chain lubricants at present used can be essentially divided into 3 main groups:
1. lubricants based on soap,
2. lubricants based on fatty amines and
3. lubricants based on synthetic tensides.
The originally used lubrication based on soaps was usable relatively without problems and gave a good lubrication and cleaning but had the disadvantage that the soap components represent a good nutrient medium for micro-organisms and, on the other hand, soaps are sensitive towards hard water so that complexing agents, for example ethylenediamine-tetrascetic acid (EDTA) must additionally be added. Furthermore, EDTA can, in addition, only be broken down with difficulty in the clarification system.
For these reasons, today there are used especially lubricant concentrates based on fatty amines, as well as amphoteric tensides (e.g. alkylaminoalkylcarboxylic acids (cf. DE 36 31 953-A1 and WO 95/33808-A1). Since these amino compounds themselves display only a small biocidal and cleaning action, in DE 36 31 953-A1 it is recommended additionally to clean and disinfect at regular intervals the plant with an acidic cleaning fluid which requires a considerable expense.
Furthermore, from WO 96/02616-A1 are known chain lubricants which consist of alkylpolyglycol phosphoric acid esters to which are additionally added aromatic biocides or quaternary ammonium compounds.
From EP 0 044 458-A1 and DE 196 42 598-A1 are known chain lubricants based on alkylpolyglycol-carboxylic acids which, alone or in admixture with other tensides, display a good lubricating and purifying action, in comparatively high concentration these products even appear to display a certain biocidal action although it is stated in DE 196 42 598-A1 that the products can be broken down not only aerobically but also anaerobically in clarification plant.
Furthermore, from EP 0 359 145-A1 are known soap-free lubricant compositions which contain alkylbenzene-sulphonates, alkoxylated alkanol phosphates and alkane-carboxylic acids, as well as usual adjuvants and to which, as disinfecting agents, are added glutaraldehyde, isothiazoline, oxy compounds or pyridinethiol oxide in 5-50% of the tensides.
The use of quaternary ammonium compounds as disinfecting agents in cleaning agents with which normally conveyor systems lubricated with fatty amines are from time to time cleaned is described in DE 36 31 953-A1. On the other hand, in DE 39 05 548-A1 it is attempted, by use of secondary and/or tertiary amines, to use lubricants which show their own biocidal action. Although these products are to show their own cleaning action, it is, nevertheless, recommended to carry out an additional cleaning from time to time with organic or inorganic acids.